Jump to content
SAU Community

Recommended Posts

Do the RB25 stock ecus have a disliking for boost?

I have a RB25 with full turbo back exhaust, pod and front mount and without a boost controller it makes a constant 0.8bar.

On really cold nights, it misses quite a bit under full load. I have heard the stock ECUs like to retard themselves when theres extra boost being pumped in. DUring the days it seems to run OK under full load.

Any ideas? Would a SAFC/SITC combo or PFC help this?

CHeers.

Link to comment
https://www.sau.com.au/forums/topic/122658-r33-gts25t-stock-ecus/
Share on other sites

well seein as i was told this just 3 days ago search!!! lol

i had the same prob, thought it was coils, but yes 33 stock ecu sucks...

had a safc2 installed and it has fixed my probs :P

pfc or safc would fix this prob i think, but theres alot more knowledgeable ppl on here that could go further in depth about it.... or a 2min search ;)

RB25 ecu's have a air flow cut not a boost cut. When you hit the cut then you will know it - the whole engine cuts out and it feels like you just slammed the brakes on.

Sounds to me by your "missing" is that the boost is putting out the spark. My advise to you would be to gap the spark plugs down to .7 or .8 and try again.

You will be suprised =)

This is a known issue with slighty modified skylines - even stock ones. Works wonders.

Do the RB25 stock ecus have a disliking for boost?

I have a RB25 with full turbo back exhaust, pod and front mount and without a boost controller it makes a constant 0.8bar.

On really cold nights, it misses quite a bit under full load. I have heard the stock ECUs like to retard themselves when theres extra boost being pumped in. DUring the days it seems to run OK under full load.

Any ideas? Would a SAFC/SITC combo or PFC help this?

CHeers.

safc only gets rid of the problem if you are running lean. if you are running rich and use a safc to lean it out you may get boost cut earlier. only way to get rid of boost cut is to get a aftermarket ecu, such as pfc, or a fuel cut defender. the new fuel cut defender from turbosmart should set you back about $230, but you then need some sort of fuel computer to stop it leaning out.

mad082 you have got it the wrong way round. SAFC only works if running rich and you are getting air flow protection.

E.g

Before SAFC:

5 volts on the AFM triggers Air flow protection and is giving 9:1 air flow ratio (rich)

After SAFC:

With the SAFC you want to lean out the fuel mixture so you intercept the AFM signal and change the 5v reading to 4.8v. This will fool the ECU that there is less load there - hence less fuel will be delivered and it may not trigger air flow protection. I.e. youmay now get 12:1 AFR and no air flow protection

Also it has to do with how quickly the rise in Air flow occurs ...e.g how quickly you go from say 3v to 5v - this may trigger Air flow protection

P.s. all values made up. But AFM reads 0-5v

0v = no air flow

5.1v = A lot of airflow (enough to make 170rwkw+)

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Just one more post to show the final result and the original "janky" solution for a laugh. Everything feels really tight and no wobbling at all, very pleased 🙂
    • After drying a few days, time to put her back together 
    • The hot exhaust light will come on not from just the cat being blocked, but it's just a temp sensor, and it's designed to warn you to not do things like park in long grass.   If you've been pushing the motor a bit, it can cause the light to come on.   Second if the cat is rattling, I'd suspect it's not blocked, but instead falling apart inside.   The easiest "fix" until you can get a cat put back in, is to unbolt your one, bash the rest of the insides out, and then bolt it back in.   For a daily driver/street car, I am in agreeance of put a cat in the car. If it were race car I wouldn't care if it were removed.
    • No worries at all 🫡 I think the most satisfying things to make are the little bits that are just impossible to find or they're no longer manufactured. Generally I always try to replace parts with OEM wherever possible. This little project is also great because it'll never see the light of day, but strengthen these brackets so it's not just relying on the little standard screws in the headlight plastic. As soon as I saw the standard brackets and screws I thought, "well I'm not going to install with just the screws, the plastic tabs will just snap off". It's crazy how expensive everything has become yeah. But I suppose that's supply and demand; granted it's a lot easier to get brand new genuine parts these days which is fantastic 😊, I don't have to get totally reamed at the local Nissan dealer ha ha We sure are lucky we have all these manufacturers making parts these days, a few really great Australian companies too like Platinum Racing Products and Fit Mint Automotive, what a time to be alive ❤️ . I've got my eye on the RB26 head by PRP as mine has a very fine hairline crack, so that'll need to be addressed some time in the future. If you have any requests or odd things to make feel free to let me know and I can have a crack at making replacement parts ✌️
×
×
  • Create New...